Selina Dicker, 37, of Ranworth, is currently at base camp and hopes to climb the mountain to raise money for charity.

A group of Sherpas had gone ahead when the avalanche hit at 6.45am local time today in an area known as the popcorn field, just above Everest base camp at 21,000ft.

Miss Dicker was in a group organised by Sheffield-based Jagged Globe, comprising nine climbers, three English guides and around 20 Sherpas and cooks.

One of the Sherpas from Miss Dicker’s group is among the deceased, and a second Sherpa from the group was airlifted to hospital in Kathmandu, Nepal’s capital city.

It is understood he has a broken shoulder and his injuries are not life-threatening.

Writing on her Facebook page, Miss Dicker said: “One of the saddest mornings I have ever witnessed, I have been hypnotised by the helicopters attempting to rescue the many Sherpas unfortunate enough to be part of the accident in the Khumbu icefall.

“I feel extremely grateful not to have been part of the accident and my heart goes out to the families and friends of all the Sherpas involved.

“They are the kindest and strongest group of people I have had the good fortune to meet.”

Miss Dicker’s father Christopher Dicker received a call from her at 8am today confirming she was safe.

He said: “I think she was quite upset.”

Tom Briggs, one of the company directors of Jagged Globe, said it was “too early to say” whether the expedition would continue after the tragedy.

Miss Dicker had flown out to Nepal at the end of March, and the team had been acclimatising at base camp for a week.

They had expected to reach the summit in the second or third week of May.

She is aiming to raise £45,000 for Operation Smile on the expedition.

The charity carries out free surgeries for youngsters born with cleft lips in more than 60 countries worldwide, and is close to her heart as both she and younger brother Mark were born with a cleft lip.

More than a dozen were killed when the avalanche swept a route used to scale the world’s highest peak, a Nepalese tourism official said.

The avalanche hit just below Mount Everest Camp 2 around 6.30am local time, Krishna Lamsal said.

All those killed and missing had gone early in the morning to the area to fix ropes for climbers along the route to the 29,000ft summit.

Hundreds of climbers and guides have gathered at the base camp, gearing up for their final attempt to scale Everest early next month when weather conditions get favourable.

The area where the avalanche occurred - at 21,000ft - is nicknamed the popcorn field.

Nepal had earlier announced several steps this year to help manage the flow of climbers, minimise congestion and speed up rescue operations.

The preparations included the dispatch of officials and security personnel to the base camp at 17,380ft, where they would stay throughout the spring climbing season that ends in May.

More than 4,000 climbers have scaled the summit since 1953, when it was first conquered by New Zealander Edmund Hillary and Sherpa Tenzing Norgay.